Thanks guys!

[BillOhio]

Thanks James. It's a relief to get it out of where my dad keeps his car and into my garage. I thought it would be home when he got back from Florida,  ah hmm, April lol. I have some kind of odd low vacuum issue and working on that. Even down to took of drivers side valve cover tonight. I understand why smog equipment  got tossed!  I don't get into getting a trophy, but enjoy going and hanging out with my friends and looking at cars. I think there were 1000 there. We have a show that big this weekend but calling for 95 degrees and it's downtown with fair sized buildings and no breeze. I can skip one.

[dale_z28]

Bill, is low vacuum messing with your brakes like it does mine? With my idle speed around 1100-1200 RPM, I seem to get one good power-assisted brake before I either have to stand on the brake pedal or blip the gas to get some vac back (this is putting around a parking lot at slow-speed obviously).

I'm going to my first show Saturday with temps expected around 97, and humidity right up there with it. I bought a canopy to sit under for shade, and we're bringing plenty of ice... I really hope this first show isn't miserable for the wife...I hate to set the tone for future ones!

[X33RS]

You may have that if timing isn't tweaked.

Mine was the same way, even with the stock 30-30 cam.  Plus living at 5,000 ft where the engine doesn't make quite as much vacuum compounds the problem.   The fix is to run more initial timing, limit the centrifugal, and run your vacuum advance to manifold vacuum source for a bit extra timing at idle, then adjust the carb accordingly.   Once setup properly the engine will produce 3-6 inches more vacuum.

For example on mine, up here at this elevation with stockish timing settings and the vacuum advance hooked to ported on the carb, my engine only made 5 inches.  Not enough for brakes.  One good stop was all it had.
   I ended up soldering the centrifugal advance slot to limit that to 16 degrees.  I set my initial timing at 20 degrees (together 36 total)   I then dialed in vacuum advance with a limiter screwed down to the rear arm on the breaker plate made out of a penny.  Old trick as they don't sell the limiter plates anymore that I can find.  Making one out of a penny takes 2 minutes.   I limit the vacuum advance to about 12 degrees this way and then run it directly to a manifold source to add 10-12 degrees to idle timing.   So technically the idle timing is about 30-32 degrees (initial plus vacuum together)   This added timing goes away however as soon as you step on the gas and vacuum drops, and you centrifugal takes over when under load.  At light throttle cruising with everything together you end up with 45-47ish timing give or take while cruising, which works perfectly, good drivability and better gas mileage.  Works fine at 11:1 with the 30-30 cam on pump gas.
   This is how I set up most distributors for customers that have large overlap camshafts, as it tends to smooth the idle a bit, makes carb tuning a bit easier, and helps the engine produce vacuum.  With a 140 cam in a little 302 it's going to need tweaks like this for best drivability.
  With these tricks my engine is now making about 12 inches of vacuum up here at 5,000 ft which is plenty for power brakes.  It stops just fine now.

Hope that helps.

[BillOhio]

Mine has 3 inches and that's off the manifold with everything else plugged. Not sure what's going on yet.

[X33RS]

Yup, that's not all that unusual with a 140 cam in a little 302.   Mine only had 5 with a 30-30 cam, granted at 5,000 feet but still...

I see this often with cars here.  I did a 69 Z last year with a cross ram and 140 cam that came in running terrible.  Same deal.  Once all dialed in it actually drove fairly decent considering the carb and intake setup (frankly not the best design IMO)  But the cool factor so it had to stay.
  Doing my fathers now, a stroker 571 street car that made 760 on pump gas.  Very radical solid roller and 6 inches of vacuum.   I'll squeeze a bit more out of it.

[BillOhio]

The Hemi in my gtx had 12 at 600 rpm with a roller and 2 carbs on open plenum intake. I have tried 2 carbs and both at 3 inches

[BillOhio]

I have added more initial advanced and didn't pick up vacuum. I did notice if I rev the motor to like 2k, vacuum went to 10. Talked to my engine guy and that puzzled him something strange happening

[m22mike]

Bill
 Great work, car is awesome, who doesn't love 69 burgandy.

Mike

[ko-lek-tor]

http://www.linnbenton.edu/auto/perform/vacuum.html
You sure you are hooked into MANIFOLD vacuum Bill? and not port?

[BillOhio]

Gauge is hooked to the booster fitting on the back of the manifold

[dale_z28]

You may have that if timing isn't tweaked.

Mine was the same way, even with the stock 30-30 cam.  Plus living at 5,000 ft where the engine doesn't make quite as much vacuum compounds the problem.   The fix is to run more initial timing, limit the centrifugal, and run your vacuum advance to manifold vacuum source for a bit extra timing at idle, then adjust the carb accordingly.   Once setup properly the engine will produce 3-6 inches more vacuum.

For example on mine, up here at this elevation with stockish timing settings and the vacuum advance hooked to ported on the carb, my engine only made 5 inches.  Not enough for brakes.  One good stop was all it had.
   I ended up soldering the centrifugal advance slot to limit that to 16 degrees.  I set my initial timing at 20 degrees (together 36 total)   I then dialed in vacuum advance with a limiter screwed down to the rear arm on the breaker plate made out of a penny.  Old trick as they don't sell the limiter plates anymore that I can find.  Making one out of a penny takes 2 minutes.   I limit the vacuum advance to about 12 degrees this way and then run it directly to a manifold source to add 10-12 degrees to idle timing.   So technically the idle timing is about 30-32 degrees (initial plus vacuum together)   This added timing goes away however as soon as you step on the gas and vacuum drops, and you centrifugal takes over when under load.  At light throttle cruising with everything together you end up with 45-47ish timing give or take while cruising, which works perfectly, good drivability and better gas mileage.  Works fine at 11:1 with the 30-30 cam on pump gas.
   This is how I set up most distributors for customers that have large overlap camshafts, as it tends to smooth the idle a bit, makes carb tuning a bit easier, and helps the engine produce vacuum.  With a 140 cam in a little 302 it's going to need tweaks like this for best drivability.
  With these tricks my engine is now making about 12 inches of vacuum up here at 5,000 ft which is plenty for power brakes.  It stops just fine now.

Hope that helps.

Thanks! You offered these tips to me before I had my car back and was relating "how it used to be" back in the day. I will investigate and probably have more questions.

I didn't intend to hijack Bill's thread, but maybe since he and I have similar problems, we may need similar solutions!

[miket1]

Hey Bill,,   the Z looks great,  good job, and you know I like the  Burgandy color.

Mike

[lynnbilodeau]

Very nice Bill.  Great looking car.

[X66]

 Awesome Z. Great to hear another one is back on the road. Drive it and enjoy it often.

[BillOhio]

https://m.youtube.com/watch?v=MS3bvWjuTiE.   Finally  got a chance to video it running.  Idle was about 900. Distributor has been recurved and one carb I have has an issue. The distributor adjustments did smooth the idle some. I drove about 40 miles to a show today and no problems.  Starts right up. Bias plies are fun and drives nice until you get to a weird place in road and it skates sideways.   .   This is Gardener exhaust with just the transverse muffler.